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ADF7242 - Retry Mechanism

Question asked by Guruditya on Jul 6, 2017
Latest reply on Jul 6, 2017 by mhennerich



I have the following query:


We have 2 ADF7242 Eval Boards with input and output connected via SMA Cables using proper attenuators.

While the two boards are communicating with each other, we suspect that the retries are not happening when there is reception/acknowledgement failure.


We tried to following setup to understand the operation

At the transmitter side we have compiled following test cases with CSMA/CA enabled:
a)We enabled auto_ack , cca retries set to 7 and frame_retries set to 5.
b)We enabled auto_ack , cca retries set to 4 and frame_retries set to 3.


Our test case is as follows:

1) We have switched the receiver off in order to get no acknowledgements.

We are expecting to see the transmitter retry each packet multiple times in this configuration. Is this correct ?

Is there anyway to turn on a debug log to see if the retry is actually happening ?


We expect the time stamp between the consecutive packets was expected to have a delay of:
a) (864us+192us)*5 (no. of retries)--for case a above
b) (864us+192us)*3 (no. of retries)---for case b above

Is our understanding correct ?

The actual results show the drive responding in 20 to 35 micro seconds in both cases. We expected the time difference should have been more as retries should have been triggered as the receiver is off (no ack).